80 Bulletin American Museum, of Natural History. [Vol. XXXVI, 



Week ending Highest Lowest Average for week. 



July 5 86 63 74f 



12 86 64 74i 



19 85 65 74 



26 89 59 74i 

 August 2 87 65 76 



9 91? 66 77 



16 90? 61 76 



23 90? 66 78 



30 80 64 771 



Sept. 6 89 65 76 



13 91 64 76i 



20 89 64 76f 



27 90 65 76i 

 Oct. 4 88 67 76 



11 86 64 76 J 



18 89 65 77 



25 88 64 75i 



Nov. 1 87 66 75 



8 87 66 76 



15 87 68 77* 



22 86 66 75 



29 86 66 76 



Dec. 6 86 65 76 



13 85 65 75 



20 87 64 76 



27 90 66 77i- 



The preceding observations were made in the Tropical Zone, but an 

 equal stability in the yearly range of temperature is shown at localities in 

 the Subtropical as well as Temperate Zones. Thus, Regel states that the 

 lowest monthly average recorded at Bogota is 57° (July, 1880), while the 

 highest, 61°, occurred in the same month of the succeeding year. 



This surprisingly small annual range in the temperature of any one 

 locality doubtless accounts for the comparatively small variation in the 

 limits of life-zones, the boundaries of which are primarily isothermal. 



It is, therefore, of importance for us to know to what extent temperature 

 is affected by altitude and I insert here the following pertinent observations 

 from Robert Blake White's 'Notes on the Central Provinces of Colombia' 

 (Proc. R. G. S., V, 1883, pp. 263, 264). 



"From a numerous series of observations of the mean temperatures at 

 different altitudes in the Cordilleras, collected from a great many observers, 

 I have formed a table of mean temperatures corresponding to a series of 

 altitudes from sea-level up to 16,400 feet in height, which will be found 

 very generally applicable over the whole of the Colombian territory. These 



